Display device

ABSTRACT

According to one embodiment, a display device includes a liquid crystal layer between a first substrate and a second substrate. The first substrate includes a wiring line and a pixel electrode. The liquid crystal layer contains a stripe-shaped polymer extending in a first direction and a liquid crystal molecule. The liquid crystal layer contains a first polymer in an area overlapping the wiring line and a second polymer in an area overlapping the pixel electrode. The first polymer includes a first portion extending in a direction different from the first direction. The second polymer includes a second portion extending in a direction different from the first direction. A density of the first portion is higher than a density of the second portion.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromJapanese Patent Application No. 2019-043826, filed Mar. 11, 2019, theentire contents of which are incorporated herein by reference.

FIELD

Embodiments described herein relate generally to a display device.

BACKGROUND

Recently, various illumination devices including light modulationelements which exhibit scattering properties or transparent propertieswith respect to light have been proposed. For example, the lightmodulation element includes a polymer dispersed liquid crystal layer asa light modulation layer. The light modulation element is disposedbehind a light guide and scatters light which enters from a side surfaceof the light guide.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view showing a configuration example of a displaydevice DSP of the present embodiment.

FIG. 2 is a plan view showing an example of a pixel PX shown in FIG. 1.

FIG. 3 is a plan view showing an example of an insulating film ILdisposed in a first substrate SUB1 shown in FIG. 2.

FIG. 4 is a cross-sectional view showing an example of a display panelPNL along line A-B including a second area A2 shown in FIG. 3.

FIG. 5 is a cross-sectional view showing an example of the display panelPNL along line C-D including a first area A1 shown in FIG. 3.

FIG. 6 is a cross-sectional view showing an example of the displaydevice DSP of the present embodiment.

FIG. 7 is a graph showing the relationship between a voltage applied toa liquid crystal layer LC of a comparative example and a degree ofscattering (luminance) of the liquid crystal layer LC.

FIG. 8 is a graph showing the relationship between a voltage applied toa liquid crystal layer LC of the present embodiment and a degree ofscattering (luminance) of the liquid crystal layer LC.

DETAILED DESCRIPTION

In general, according to one embodiment, there is provided a displaydevice including a light-emitting element, a first substrate, a secondsubstrate, and a liquid crystal layer. The first substrate includes afirst transparent substrate, a wiring line located above the firsttransparent substrate, a switching element electrically connected to thewiring line, and a pixel electrode electrically connected to theswitching element. The second substrate includes a second transparentsubstrate having a side surface facing the light-emitting element, and acommon electrode overlapping the pixel electrode. The liquid crystallayer is located between the first substrate and the second substrate,and contains a stripe-shaped polymer extending in a first direction anda liquid crystal molecule. The liquid crystal layer contains a firstpolymer in an area overlapping the wiring line and a second polymer inan area overlapping the pixel electrode. The first polymer includes afirst portion extending in a direction different from the firstdirection. The second polymer includes a second portion extending in adirection different from the first direction. A density of the firstportion is higher than a density of the second portion.

According to another embodiment, there is provided a display deviceincluding a light-emitting element, a first substrate, a secondsubstrate, and a liquid crystal layer. The first substrate includes afirst transparent substrate, a grid-shaped insulating film located abovethe first transparent substrate and defining an opening, and a pixelelectrode located in the opening. The second substrate includes a secondtransparent substrate having a side surface facing the light-emittingelement, and a common electrode overlapping the pixel electrode. Theliquid crystal layer is located between the first substrate and thesecond substrate, and contains a stripe-shaped polymer extending in afirst direction and a liquid crystal molecule. The liquid crystal layercontains a first polymer in an area overlapping the insulating film anda second polymer in an area overlapping the opening. A density of thefirst polymer is higher than a density of the second polymer.

The present embodiment will be described hereinafter with reference tothe accompanying drawings. The disclosure is merely an example, andproper changes in keeping with the spirit of the invention, which areeasily conceivable by a person of ordinary skill in the art, come withinthe scope of the invention as a matter of course. In addition, in somecases, in order to make the description clearer, the widths,thicknesses, shapes, and the like of the respective parts areillustrated schematically in the drawings, rather than as an accuraterepresentation of what is implemented, but such schematic illustrationis merely exemplary, and in no way restricts the interpretation of theinvention. Furthermore, in the specification and drawings, structuralelements which function in the same or a similar manner to thosedescribed in connection with preceding drawings are denoted by the samereference numbers, and detailed explanations of them that are consideredredundant may be arbitrarily omitted.

FIG. 1 is a plan view showing a configuration example of a displaydevice DSP of the present embodiment. A first direction X, a seconddirection Y and a third direction Z are, for example, orthogonal to oneanother but may cross at an angle other than 90 degrees. The firstdirection X and the second direction Y correspond to directions parallelto the main surface of a substrate constituting the display device DSP,and the third direction Z corresponds to the thickness direction of thedisplay device DSP. In the present embodiment, viewing an X-Y planedefined by the first direction X and the second direction Y will bereferred to as planar view.

In the present embodiment, a liquid crystal display device employingpolymer dispersed liquid crystal will be described as an example of thedisplay device DSP. The display device DSP includes a display panel PNL,a wiring substrate 1, an IC chip 2 and a plurality of light-emittingelements LD.

The display panel PNL includes a first substrate SUB1, a secondsubstrate SUB2, a liquid crystal layer LC and a sealant SE. Each of thefirst substrate SUB1 and the second substrate SUB2 has the shape of aflat plate parallel to the X-Y plane. The first substrate SUB1 and thesecond substrate SUB2 overlap in planar view. The first substrate SUB1and the second substrate SUB2 are bonded together by a sealant SE. Theliquid crystal layer LC is held between the first substrate SUB1 and thesecond substrate SUB2 and is sealed in by the sealant SE. In FIG. 1, theliquid crystal layer LC and the sealant SE are indicated by differentdiagonal lines.

As shown in an enlarged schematic view within FIG. 1, the liquid crystallayer LC includes polymer dispersed liquid crystal containing polymers31 and liquid crystal molecules 32. For example, the polymers 31 areliquid crystal polymers. The polymers 31 have the shape of a stripeextending in the first direction X and are arranged in the seconddirection Y. The liquid crystal molecules 32 are dispersed in the gapsof the polymers 31 and are aligned such that major axes of them becomeparallel to the first direction X. The polymers 31 and the liquidcrystal molecules 32 have optical anisotropy or refractive anisotropy.The responsiveness to an electric field of the polymers 31 is lower thanthe responsiveness to an electric field of the liquid crystal molecules32.

For example, the alignment direction of the polymers 31 hardly changesregardless of the presence or absence of an electric field. On the otherhand, the alignment direction of the liquid crystal molecules 32 changesaccording to an electric field in a state where a high voltage ofgreater than or equal to a threshold value is applied to the liquidcrystal layer LC. In a state where voltage is not applied to the liquidcrystal layer LC, the optical axis of the polymer 31 and the opticalaxis of the liquid crystal molecule 32 are parallel to each other, andlight which enters the liquid crystal layer LC is transmitted throughthe liquid crystal layer LC and is hardly scattered in the liquidcrystal layer LC (transparent state). In a state where voltage isapplied to the liquid crystal layer LC, the optical axis of the polymer31 and the optical axis of the liquid crystal molecule 32 cross eachother, and light which enters the liquid crystal layer LC is scatteredin the liquid crystal layer LC (scattering state).

The display panel PNL includes a display portion DA in which an image isdisplayed, and a frame-shaped non-display portion NDA which surroundsthe display portion DA. The sealant SE is located in the non-displayportion NDA. The display portion DA includes pixels PX arrayed in amatrix in the first direction X and the second direction Y.

As shown in an enlarged view within FIG. 1, each pixel PX includes aswitching element SW, a pixel electrode PE, a common electrode CE, aliquid crystal layer LC and the like. The switching element SW iscomposed of, for example, a thin-film transistor (TFT) and iselectrically connected to a scanning line G and a signal line S. Thescanning line G is electrically connected to the switching elements SWdisposed respectively in the pixels PX arranged in the first directionX. The signal line S is electrically connected to the switching elementsSW disposed respectively in the pixels PX arranged in the seconddirection Y. The pixel electrode PE is electrically connected to theswitching element SW. The common electrode CE is commonly disposed forthe pixel electrodes PE. Each pixel electrode PE faces the commonelectrode CE in the third direction Z. The liquid crystal layer LC (morespecifically, the liquid crystal molecules 32) is driven by an electricfield generated between the pixel electrode PE and the common electrodeCE. Capacitance CS is formed, for example, between an electrode havingthe same potential as the common electrode CE and an electrode havingthe same potential as the pixel electrode PE.

As will be described later, the scanning line G, the signal line S, theswitching element SW and the pixel electrode PE are disposed in thefirst substrate SUB1, and the common electrode CE is disposed in thesecond substrate SUB2. In the first substrate SUB1, the scanning line Gand the signal line S are electrically connected to the wiring substrate1 or the IC chip 2.

The wiring substrate 1 is mounted on an extension portion Ex of thefirst substrate SUB1. The extension portion Ex corresponds to part ofthe first substrate SUB1 which does not overlap the second substrateSUB2. The wiring substrate 1 is, for example, a bendable flexibleprinted circuit. The IC chip 2 is mounted on the wiring substrate 1. Inthe IC chip 2, for example, a display driver which outputs a signalnecessary for image display is incorporated. Note that the IC chip 2 maybe mounted on the extension portion Ex.

The light-emitting elements LD overlap the extension portion Ex inplanar view. The light-emitting elements LD are spaced apart from oneanother and are arranged in the first direction X. Each light-emittingelement LD is, for example, a light-emitting diode, and although notdescribed in detail, each light-emitting element LD includes a redlight-emitting portion, a green light-emitting portion and a bluelight-emitting portion. These light-emitting elements LD are arrangedalong an end portion E21 of the second substrate SUB2 and emit lighttoward the end portion E21. The end portion E21 extends in the firstdirection X in planar view.

FIG. 2 is a plan view showing an example of the pixel PX shown inFIG. 1. The first substrate SUB1 includes scanning lines G1 and G2,signal lines S1 and S2, the switching element SW and the pixel electrodePE.

The scanning lines G1 and G2 are spaced apart from each other and arearranged in the second direction Y. The signal lines S1 and S2 cross thescanning lines G1 and G2, and are spaced apart from each other and arearranged in the first direction X. Here, it is assumed that theextension direction of the scanning lines G1 and G2 is the firstdirection X and the extension direction of the signal lines S1 and S2 isthe second direction Y. The pixel PX shown in FIG. 2 corresponds to anarea defined by the scanning lines G1 and G2 which are adjacent to eachother and the signal lines S1 and S2 which are adjacent to each other.

The switching element SW is disposed in a portion in which the scanningline G1 and the signal line S1 cross each other. The switching elementSW includes a semiconductor layer SC. The semiconductor layer SCoverlaps a gate electrode SWG which is integrally formed with thescanning line G1. A source electrode SWS which is integrally formed withthe signal line S1, and a drain electrode SWD are electrically connectedto the semiconductor layer SC. The pixel electrode PE is disposedbetween the scanning lines G1 and G2 and between the signal lines S1 andS2. The pixel electrode PE overlaps the drain electrode SWD and iselectrically connected to the switching element SW via a contact holeCH.

FIG. 3 is a plan view showing an example of an insulating film ILdisposed in the first substrate SUB1 shown in FIG. 2. The insulatingfilm IL has the shape of a grip which defines openings OP, respectively,in the pixels PX. That is, the insulating film IL has portions ILXextending in the first direction X and portions ILY extending in thesecond direction Y. The insulating film IL overlaps the scanning linesG1 and G2, the signal lines S1 and S2 and the switching element SW. InFIG. 3, the pixel electrode PE indicated by a dot-dash line is disposedso as to overlap the opening OP. The periphery of the pixel electrode PEoverlaps the portions ILX and the portions ILY. The contact hole CHshown in FIG. 2 is formed in the opening OP. The insulating film IL is,for example, an organic insulating film but may be an inorganicinsulating film.

When planarly viewed in the X-Y plane, a polymer in a first area A1overlapping the scanning line G1 which is an example of a wiring line ora polymer in a first area A1 overlapping the insulating film IL amongthe polymers 31 in the liquid crystal layer LC corresponds to a firstpolymer 31A shown in an enlarged view within FIG. 3. A polymer in asecond area A2 overlapping the pixel electrode PE or a polymer in asecond area A2 overlapping the opening OP corresponds to a secondpolymer 31B shown in an enlarged view within FIG. 3. The density of thefirst polymer 31A is higher than the density of the second polymer 31B.The first polymer 31A and the second polymer 31B are formed of the samematerial. That is, the first polymer 31A and the second polymer 31B areformed of the same monomer.

The density of each of the first polymer 31A and the second polymer 31Bhere is defined by the number of stripe-shaped polymers per unit area orthe total length of stripe-shaped polymers per unit area when the liquidcrystal layer LC is planarly viewed in the X-Y plane.

Note that the density of the present embodiment may be defined by thenumber of stripe-shaped polymers per unit area or the total length ofstripe-shaped polymers per unit area when the liquid crystal layer LC iscross-sectionally viewed in an X-Z plane or a Y-Z plane. Alternatively,the density of the present embodiment may be defined by the number ofstripe-shaped polymers per unit volume, the total length ofstripe-shaped polymers per unit volume or the volume of stripe-shapedpolymers per unit volume.

FIG. 4 is a cross-sectional view showing an example of the display panelPNL along line A-B including the second area A2 shown in FIG. 3.

The first substrate SUB1 includes a transparent substrate (firsttransparent substrate) 10, insulating films 11 and 12, the signal linesS1 and S2, the insulating film IL, a capacitance electrode C, the pixelelectrode PE and an alignment film AL1. The insulating film 11 isdisposed on the upper surface of the transparent substrate 10. Thesignal lines S1 and S2 are disposed on the insulating film 11 and arecovered with the portions ILY of the insulating film IL. The capacitanceelectrode C is disposed on the insulating film 11 in the opening OP andis covered with the insulating film 12. In addition, the capacitanceelectrode C overlaps the portions ILY and face the signal lines S1 andS2. The capacitance electrode C is in contact with the insulating film11 and the insulating film IL. The pixel electrode PE is disposed on theinsulating film 12 in the opening OP and is covered with the alignmentfilm AL1. That is, the capacitance electrode C is disposed between thetransparent substrate 10 and the pixel electrode PE. The pixel electrodePE faces the capacitance electrode C via the insulating film 12 andforms the capacitance CS of the pixel PX. The contact hole CH shown inFIG. 2 penetrates the insulating film 12. The alignment film AL1 is incontact with the liquid crystal layer LC.

The second substrate SUB2 includes a transparent substrate (secondtransparent substrate) 20, the common electrode CE and an alignment filmAL2. The common electrode CE is disposed on the main surface of thetransparent substrate 20 and is covered with the alignment film AL2. Inthe second substrate SUB2, a light-shielding layer may be disposed atpositions located directly above the switching element SW, the scanningline G and the signal line S, respectively. In addition, a transparentinsulating film may be disposed between the transparent substrate 20 andthe common electrode CE or between the common electrode CE and thealignment film AL2. The common electrode CE faces the pixel electrodesPE. In addition, the common electrode CE is electrically connected tothe capacitance electrode C and has the same potential as thecapacitance electrode C. The alignment film AL2 is in contact with theliquid crystal layer LC.

The liquid crystal layer LC is disposed between the first substrate SUB1and the second substrate SUB2. The liquid crystal layer LC contains thestripe-shaped second polymer 31B and the liquid crystal molecules 32.

FIG. 5 is a cross-sectional view showing an example of the display panelPNL along line C-D including the first area A1 shown in FIG. 3. Thefirst substrate SUB1 further includes the scanning line G1. The scanningline G1 is disposed on the upper surface of the transparent substrate 10and is covered with the insulating film 11. The portion ILX of theinsulating film IL is disposed directly above the scanning line G1. Theportion ILX is disposed on the insulating film 11. The capacitanceelectrode C overlaps the portion ILX. That is, the insulating film 11and the insulating film IL are interposed between the scanning line G1and the capacitance electrode C. In addition, the insulating film IL isinterposed between the signals S1 and S2 and the capacitance electrodeC.

As shown in FIGS. 4 and 5, the second substrate SUB2 does not include alight-shielding layer at positions overlapping the scanning line G1 andthe signal lines S1 and S2 which are examples of wiring lines,respectively.

The liquid crystal layer LC contains the stripe-shaped first polymer 31Aand the liquid crystal molecules 32. As shown in FIGS. 4 and 5, when theliquid crystal layer LC is cross-sectionally viewed in the X-Z plane,the density of the first polymer 31A is higher than the density of thesecond polymer 31B.

In addition, the first polymer 31A includes a first portion 311extending in a direction different from the first direction X. Thesecond polymer 31B shown in FIG. 4 includes a second portion 312extending in a direction different from the first direction X. The firstportion 311 here may be part of the stripe-shaped first polymer 31A ormay be a portion branching off from the stripe-shaped first polymer 31A.The second portion 312 here may be part of the stripe-shaped secondpolymer 31B or may be a portion branching off from the stripe-shapedsecond polymer 31B. The direction different from the first portion Xhere may be the second direction Y, may be the third direction Z or maybe a direction different from the second direction Y and the thirddirection Z. The density of the first portion 311 is higher than thedensity of the second portion 312. The length of the first portion 311branching off from a portion extending in the first direction X in thefirst polymer 31A is greater than the length of the second portion 312branching off from a portion extending in the first direction X in thesecond polymer 31B.

The density of each of the first portion 311 and the second portion 312here is defined by the number of portions per unit area or the totallength of portions per unit area when the liquid crystal layer LC iscross-sectionally viewed in the X-Z plane.

Note that the density of the present embodiment may be defined by thenumber of portions per unit area or the total length of portions perunit area when the liquid crystal layer LC is planarly viewed in the X-Yplane. Alternatively, the density of the present embodiment may bedefined by the number of portions per unit area or the total length ofportions per unit area when the liquid crystal layer LC iscross-sectionally viewed in the Y-Z plane. Alternatively, the density ofthe present embodiment may be defined by the number of portions per unitvolume, the total length of portions per unit volume or the volume ofportions per unit volume.

Each of the transparent substrates 10 and 20 is an insulating substratesuch as a glass substrate or a plastic substrate. The insulating film 11is, for example, a transparent inorganic insulating film of siliconoxide, silicon nitride, silicon oxynitride or the like. The insulatingfilm IL is, for example, a transparent organic insulating film ofacrylic resin or the like. The insulating film 12 is a transparentinorganic insulating film of silicon nitride or the like. Each of thecapacitance electrode C, the pixel electrode PE and the common electrodeCE is a transparent electrode formed of a transparent conductivematerial such as indium tin oxide (ITO) or indium zinc oxide (IZO). Eachof the alignment films AL1 and AL2 is a horizontal alignment film havingan alignment restriction force substantially parallel to the X-Y plane.For example, the alignment films AL1 and AL2 are subjected to alignmenttreatment in the first direction X. Note that the alignment treatmentmay be rubbing treatment or may be photoalignment treatment.

FIG. 6 is a cross-sectional view showing an example of the displaydevice DSP of the present embodiment. With regard to the display panelPNL, only main parts of it are illustrated in the drawing.

In the first substrate SUB1, the pixel electrode PE is disposed for eachpixel PX. In the second substrate SUB2, the common electrode CE isdisposed over the pixels PX and faces the pixel electrodes PE in thethird direction Z.

A transparent substrate 30 is bonded to the transparent substrate 20 bya transparent adhesive layer AD. The transparent substrate 20 is locatedbetween the liquid crystal layer LC and the transparent substrate 30 inthe third direction Z. Note that the transparent substrate 30 may beomitted.

The transparent substrate 30 is an insulating substrate such as a glasssubstrate or a plastic substrate and has substantially the samerefractive index as the transparent substrate 20. The adhesive layer ADhas substantially the same refractive index as the transparentsubstrates 20 and 30. Note that “substantially the same” here is notlimited to a case where the refractive index difference is zero butincludes a case where the refractive index difference is less than orequal to 0.03.

The transparent substrate 10 has a side surface 100, the transparentsubstrate 20 has a side surface 20C, and the transparent substrate 30has a side surface 30C. The side surface 20C corresponds to the endportion E21 of the second substrate SUB2 shown in FIG. 1. The sidesurface 100, the side surface 20C and the side surface 30C extend in thefirst direction X. The extension portion Ex corresponds to an arealocated between the side surface 100 and the side surface 200 in thesecond direction Y. The side surface 30C is located directly above theside surface 20C.

The light-emitting element LD faces the side surface 20C and the sidesurface 30C in the second direction Y. The light-emitting element LD iselectrically connected to a wiring substrate F. Note that a transparentlight guide may be disposed between the light-emitting element LD andthe side surfaces 20C and 30C.

Next, light L1 emitted from the light-emitting element LD will bedescribed with reference to FIG. 6.

The light-emitting element LD emits light L1 toward the side surfaces20C and 30C. The light L1 which is emitted from the light-emittingelement LD travels in the direction of an arrow indicating the seconddirection Y, and enters the transparent substrate 20 from the sidesurface 20C and enters the transparent substrate 30 from the sidesurface 30C. The light L1 which enters each of the transparentsubstrates 20 and 30 travels through the display panel PNL while it isrepeatedly reflected. The light L1 which enters the liquid crystal layerLC to which voltage is not applied is transmitted through the liquidcrystal layer LC and is hardly scattered in the liquid crystal layer LC.In addition, the light L1 which enters the liquid crystal layer LC towhich voltage is applied is scattered in the liquid crystal layer LC.The display device DSP can be observed from the transparent substrate 10side and can also he observed from the transparent substrate 30 side. Inaddition, regardless of whether the display device DSP is observed fromthe transparent substrate 10 side or the display device DSP is observedfrom the transparent substrate 30 side, the background of the displaydevice DSP can be observed through the display device DSP.

According to the present embodiment, the density of the first polymer31A shown in FIG. 5 is higher than the density of the second polymer 31Bshown in FIG. 4, and the density of the first portion 311 included inthe first polymer 31A is higher than the density of the second portion312 included in the second polymer 31B. As a result, in the first areaA1 overlapping a wiring line (for example, a scanning line), themovement of the liquid crystal molecules 32 is more likely to berestricted by the first polymer 31A. Therefore, in the first area A1,the liquid crystal molecules 32 are maintained in an initial alignmentstate (that is, maintained in a state in which a voltage of less than athreshold value is applied to the liquid crystal layer LC).Consequently, in the first area A1 of the liquid crystal layer LC, atransparent state is maintained, and degradation in display quality byundesired scattering can be suppressed.

In addition, when light emitted from the light-emitting element LDpropagates in the second direction Y, a loss of light by undesiredscattering can be suppressed.

Furthermore, since undesired scattering in the first area A1 issuppressed, a light-shielding layer overlapping wiring lines can beomitted, and the transmittance of the display panel PNL in a transparentstate can be improved.

On the other hand, in the second area A2 overlapping the pixel electrodePE, the movement of the liquid crystal molecules 32 is smooth ascompared to the first area A1. Therefore, in the second area A2, theresponsiveness to voltage of the liquid crystal molecules 32 isimproved.

FIG. 7 is a graph showing the relationship between the voltage appliedto the liquid crystal layer LC and the degree of scattering (luminance)of the liquid crystal layer LC. Note that FIG. 7 shows the relationshipbetween the voltage and the degree of scattering in a display panel of acomparative example. In a liquid crystal layer provided in the displaypanel of the comparative example, an area overlapping a pixel electrodePE contains a high-density first polymer 31A as is the case with thefirst area A1 of FIG. 3.

A solid curve C1 in the graph corresponds to the degree of scattering ina case where the voltage applied to the liquid crystal layer LC isincreased to a predetermined value. On the other hand, a dashed curve C2in the graph corresponds to the degree of scattering in a case where thevoltage applied to the liquid crystal layer LC is reduced from thepredetermined value.

In both of the curves C1 and C2, the degree of scattering increases asthe voltage increases, and the degree of scattering is saturated whenthe voltage is sufficiently increased. From the perspective of displayquality, the curve C1 and the curve C2 should preferably match. However,in the example shown in FIG. 7, the curve C1 and the curve C2substantially match in a high-voltage region, but the degree ofscattering of the curve C2 is higher than the degree of scattering ofthe curve C1 at the same voltage in a low-voltage region. It is presumedthat such hysteresis of responsiveness occurs because the liquid crystalmolecules 32 aligned in a direction different from an initial alignmentdirection by voltage application are restrained by the polymers 31around the liquid crystal molecules 32, and even when the voltageapplied to the liquid crystal layer LC is reduced, the liquid crystalmolecules 32 are less likely to be restored to their original alignmentstates.

FIG. 8 is a graph showing the relationship between the voltage appliedto the liquid crystal layer LC and the degree of scattering (luminance)of the liquid crystal layer LC. Note that the relationship between thevoltage and the degree of scattering in the display panel of the presentembodiment is shown in FIG. 8.

According to the present embodiment, it is confirmed that the curve C1and the curve C2 substantially match from a low-voltage region to ahigh-voltage region. That is, as described above, in the liquid crystallayer LC in the area overlapping the pixel electrode PE, the density ofthe polymers 31 around the liquid crystal molecules 32 is not too highto restrain the liquid crystal molecules 32.

Therefore, the liquid crystal molecules 32 aligned in a directiondifferent from an initial alignment direction by voltage application canbe quickly restored to their original alignment states when the voltageapplied to the liquid crystal layer LC is reduced. Consequently,hysteresis of responsiveness is suppressed. In addition, burn which canbe caused by the above-described hysteresis can be suppressed.

As described above, a display device which can suppress degradation indisplay quality can be provided according to the present embodiment.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the inventions. Indeed, the novel embodiments described hereinmay be embodied in a variety of other forms; furthermore, variousomissions, substitutions and changes in the form of the embodimentsdescribed herein may be made without departing from the spirit of theinventions. The accompanying claims and their equivalents are intendedto cover such forms or modifications as would fall within the scope andspirit of the inventions.

What is claimed is:
 1. A display device comprising: a light-emittingelement; a first substrate comprising a first transparent substrate, awiring line located above the first transparent substrate, a switchingelement electrically connected to the wiring line, and a pixel electrodeelectrically connected to the switching element; a second substratecomprising a second transparent substrate having a side surface facingthe light-emitting element, and a common electrode overlapping the pixelelectrode; and a liquid crystal layer located between the firstsubstrate and the second substrate, and containing a stripe-shapedpolymer extending in a first direction and a liquid crystal molecule,wherein the liquid crystal layer contains a first polymer in an areaoverlapping the wiring line and a second polymer in an area overlappingthe pixel electrode, the first polymer includes a first portionextending in a direction different from the first direction, the secondpolymer includes a second portion extending in a direction differentfrom the first direction, and a density of the first portion is higherthan a density of the second portion.
 2. The display device of claim 1,wherein a density of the first polymer is higher than a density of thesecond polymer.
 3. The display device of claim 1, wherein the wiringline is a scanning line extending in the first direction.
 4. The displaydevice of claim 1, wherein the second substrate does not comprise alight-shielding layer at a position overlapping the wiring line.
 5. Thedisplay device of claim 1, wherein the side surface extends in the firstdirection in planar view.
 6. The display device of claim 1, wherein thefirst polymer and the second polymer are formed of a same material. 7.The display device of claim 1, wherein a length of the first portionbranching off from a portion extending in the first direction in thefirst polymer is greater than a length of the second portion branchingoff from a portion extending in the first direction in the secondpolymer.
 8. A display device comprising: a light-emitting element; afirst substrate comprising a first transparent substrate, a grid-shapedinsulating film located above the first transparent substrate anddefining an opening, and a pixel electrode located in the opening; asecond substrate comprising a second transparent substrate having a sidesurface facing the light-emitting element, and a common electrodeoverlapping the pixel electrode; and a liquid crystal layer locatedbetween the first substrate and the second substrate, and containing astripe-shaped polymer extending in a first direction and a liquidcrystal molecule, wherein the liquid crystal layer contains a firstpolymer in an area overlapping the insulating film and a second polymerin an area overlapping the opening, and a density of the first polymeris higher than a density of the second polymer.
 9. The display device ofclaim 8, wherein the first polymer includes a first portion extending ina direction different from the first direction, the second polymerincludes a second portion extending in a direction different from thefirst direction, and a density of the first portion is higher than adensity of the second portion.
 10. The display device of claim 9,wherein the first substrate further comprises a scanning line, a signalline crossing the scanning line, and a switching element electricallyconnected to the scanning line and the signal line, and the insulatingfilm is an organic insulating film and overlaps the scanning line, thesignal line and the switching element.
 11. The display device of claim10, wherein the first substrate further comprises a first inorganicinsulating film covering the scanning line and interposed between thescanning line and the signal line, and a capacitance electrode being incontact with the first inorganic insulating film in the opening.
 12. Thedisplay device of claim 11, wherein the first inorganic insulating filmand the insulating film are interposed between the scanning line and thecapacitance electrode, and the insulating film is interposed between thesignal line and the capacitance electrode.
 13. The display device ofclaim 12, wherein the first substrate further comprises a secondinorganic insulating film interposed between the capacitance electrodeand the pixel electrode.
 14. The display device of claim 13, wherein thesecond substrate does not comprise a light-shielding layer at positionsoverlapping the scanning line and the signal line.
 15. The displaydevice of claim 8, wherein the side surface extends in the firstdirection in planar view.
 16. The display device of claim 8, wherein thefirst polymer and the second polymer are formed of a same material. 17.The display device of claim 8, wherein the first polymer includes afirst portion branching off from a portion extending in the firstdirection, the second polymer includes a second portion branching offfrom a portion extending in the first direction, and a length of thefirst portion is greater than a length of the second portion.